1. Field of the Invention
The present invention relates to a circuit breaker, and more particular to a circuit breaker assembly responsive to both current overload and thermal overheat/over-cold, which can switch off automatically not only in dependence on the occurrence of an excess current, but also when the temperature of a predetermined surrounding zone is overheated or over-cooled.
2. Description of Related Art
Most electrical appliances break down because of overheating. Overheating of an appliance or a circuit frequently causes fire or electrical shock. In order to provide a kind of protection, most houseware appliances use a fuse to prevent the overheating of the electrical wires. For the building circuitry, the bi-metal type circuit breakers are the most common devices installed in the control panels to prevent the overheating of the electrical wiring.
Circuit breakers, such as that disclosed in U.S. Pat. No. 4,167,720, are generally used to protect electrical circuits by automatically switching off on the occurrence of any excess of current. In the other words, those conventional circuit breakers are substantially the electrical current protectors to prevent overheating of the electrical wiring due to the excess current or overloaded current.
However, the surrounding around the electrical appliance connected to the electrical circuit has nothing to protect against overheating or over-cooling. It will also create a danger of fire or breaking down situation. For examples, a halogen floor lamp would generate a great amount of heat therearound that has a high risk of burning stuff like the curtain around; a heater is an appliance for generating heat. However, the user can only control the heat by setting the power output or the timer control. It is relatively expensive and difficult to control the heater according to the actual temperature around the heater.
In fact, every electrical appliance that generates heat needs a thermal guard to prevent the surrounding being overheated or over-cooled. It would be a remarkable matter if the circuit breaker can also switch off the circuit if the monitoring surrounding is too hot or too cold. It not only can prolong the service life of the electrical appliances, but also can help the user to avoid unreasonable hazard or damages.